The term "polyphenylene ether resin" includes a family of polymers well known to those skilled in the art, they are made by a variety of catalytic and non-catalytic processes from the corresponding phenols or reactive derivatives thereof. By way of illustration, certain of the following polyphenylene ethers are discussed in Hay, U.S. Pat. Nos. 3,306,874 and 3,306,855, and in Stamatoff, U.S. Pat. No. 3,257,357 and 3,257,358. Also, the Bennett and Copper patents, U.S. Pat. No. 3,639,656, 3,642,699 and 3,661,848 describe processes for the preparation of polyphenylene ethers. Other disclosures relating to processes using metal-amine catalysts are found in Bussink et al, U.S. Pat. No. 3,337,499; Blanchard et al, U.S. Pat. No. 3,219,626; Laakso et al, U.S. Pat. No. 3,342,892; Borman, U.S. Pat. No. 3,344,166; Hori et al, U.S. Pat. No. 3,384,619; Faurote et al, U.S. Pat. No. 3,400,217; and disclosures relating to metal based catalysts which do not include amines, are well known from patents such as Wieden et al, U.S. Pat. No. 3,442,885 (copper-amidines); Nakashio et al, U.S. Pat. No. 3,573,257 (metal-alcoholate or phenolate); Kobayashi et al, U.S. Pat. No. 3,455,880 (cobalt chelates); and the like. In the Stamatoff patents, the polyphenylene ethers are produced by reacting the corresponding phenolate ion with an initiator, such as peroxy acid salt, an acid peroxide, a hypohalite, and the like, in the presence of a complexing agent. Disclosures relating to non-catalytic processes, such as oxidation with lead dioxide, silver oxide, etc., are described in Price et al, U.S. Pat. No. 3,382,212. All of the patents which are mentioned above are incorporated herein by reference.
The Cizek patent, U.S. Pat. No. 3,383,435 discloses blends of polyphonylene ether resins and styrene resins. The thermoplastic compositions disclosed by Cizek may include rubber-modified styrene resin, as well as crystal polystyrene. The Carmelite, Kramer and Lee, Jr. patent, U.S. Pat. No. 3,787,532, also discloses polyphenylene ether containing compositions. These patents are also incorporated by reference.
U.S. Pat. No. 3,660,531 discloses compositions of a polyphenylene ether styrene resin and a styrene-butadiene-styrene block copolymer. These compositions have a major proportion of polyphenylene ether polymer.
There have been many attempts to upgrade the heat distortion temperature and the impact resistance of vinyl aromatic resins. One approach has been to provide copolymers of the vinyl aromatic compounds with .alpha.,.beta.-unsaturated cyclic anhydrides. In the case of styrene-maleic anhydride copolymers, a level of 20% of maleic anhydride increases the heat distortion temperature but the resulting material is very brittle.
Accordingly, it is a principal object to provide improved compositions of vinyl aromatic resins that have higher heat distortion temperatures and better impact strengths particularly as measured in terms of the Gardner impact tests.